Vehicle Visibility is keeping your car seen by other drivers.

Keeping your car visible
won't compensate for unsafe driving habits,though good vehicle
visibility will reduce your chance of a collision because other drivers
will see you sooner and avoid coming into your path.

Keep headlights on at all times

Some will argue to keep your headlights off during daylight because it
saves gas. While this may be true, wouldn't it be worth a little more
gas to avoid a serious crash because another driver didn't see you?

It is said headlights on during the day reduces your chance of a collision by about 25%.

Headlights light about 350 feet of dark road. That would be about the length of a block that could fit four or five houses. BUT....

You can see a vehicle coming ahead with its headlights for over half a mile, that's more than 2600 feet!

Where I notice the difference in Vehicle visibility using headlights the
most, is when I am facing toward the sun and am coming into a shaded
area.

The blinding sun, with a darker road makes it more
difficult to see other vehicles, but I can see those with headlights on
in those shaded roads MUCH better than those without lights on.

Also when coming around turns and curves, your headlights will
reflect off of objects on the side of the street like parked cars,
making you visible before your car is even seen.

Another advantage of your headlights on during the day is that
your tail lights will also be on, making you more visible to drivers
behind you. Tail lights are visible from at least 500 feet away, that's
a block that would fit about 7 houses.

Increase your vehicle visibility by using headlights at all times.

Below are two pictures that demonstrate the increased visibility of headlights on in daylight.

In the picture to the left notice the oncoming vehicles in the inside
lane, one about 1/4 block from where the picture is taken and another
about 1/4 block further back. Both have their headlights on.Notice how much brighter they stand out than those vehicles to the right of them with no headlights on.

In
the picture on the right, you can tell it is an even brighter, sunnier
day . If you look to the left behind the oncoming white truck/SUV you
can barely see a white speck in the distance, just past the vehicle in
the center on the right side of the road.

That, my friend, is an oncoming vehicle at least 1/2 mile or more away with its' headlights on!
An enlarged picture makes it clear it is an oncoming vehicle. I regret I
couldn't post a larger picture without distorting it too much.

Position your vehicle for the best visibility.

Blind spots

When you are driving on roads with multiple lanes of traffic, make sure you are not driving in any vehicles blind spot.

This is just near the back end of any vehicle.

Keep at least a car length distance between you and the car next to you.They could make a lane change without seeing you.

It is also more difficult for other drivers to see you if you are
driving right beside them. The best vehicle visibility other drivers
have of your car is when you are either about 2 car lengths ahead or
behind in the adjacent lane.

At intersections

Many things can block the view of your car at intersections.

Buildings and large shrubs can make it difficult for others to see you,
as well as for you to see others when stopped or when passing through an
intersection.

When you can see objects that hide your view from
drivers stopped on side streets, come slower, letting off the gas pedal,
being ready to brake if someone comes out who didn't see you.

When stopped at an
intersection with multiple lanes, if a large vehicle is to either side
of you, not only does it block your vision, but it blocks others vision
of you.

Position your car so others can see you better around larger vehicles.

There are two ways you can do this. First, you can creep forward so the
front of your car comes slightly past the front of the vehicle beside
you.

In the top picture below you can see the vehicles are roughly four to five feet apart.

In the picture to the left the Echo is slightly further back than the
Caravan. You can barely see it through the vans windows (even less so
with people sitting in the van).

In the picture to the right the Echo is forward just about two feet, but see how much more visible it is over the van!

The second way to have more vehicle visibility when stopped at an intersection, is by positioning further away from the side of the vehicle next to you (more right if the vehicle is on your left and more left if the vehicle is on your right.)

5 feet away

In these three pictures the vehicles bumpers are aligned the same, but in each picture the Echo is spaced a little further away.

10 feet away

Notice you can see more of the Echo over the top of the van, the further to the right the Echo is.

15 feet away

15 feet away is one full average highway lane width.
Notice you can start seeing the windshield at this distance.

Also remember what you see through the van windows in the pictures would be blocked by passengers in the van.
* A quote on an engineer forum, by Johan van Niekerk:
Some vehicles are nearly invisible when seen from the front or the rear. Sideways most vehicles are invisible at night.